Revert "Load only the current product config makefile."

This reverts commit 54fa8c3ff9b1f0f1b0b9c551be864f1b7378c7fc.

Conflicts:
	core/product_config.mk

Change-Id: Ia942d826eae08429d91bbfbb6c43b1cdd78563f7

Conflicts:
	core/product_config.mk